From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-7.2 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,MENTIONS_GIT_HOSTING,SPF_HELO_NONE,SPF_PASS, USER_AGENT_SANE_1 autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id CE471C2D0B1 for ; Thu, 6 Feb 2020 10:32:04 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id A081E206CC for ; Thu, 6 Feb 2020 10:32:04 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728493AbgBFKcE (ORCPT ); Thu, 6 Feb 2020 05:32:04 -0500 Received: from lhrrgout.huawei.com ([185.176.76.210]:2385 "EHLO huawei.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1728304AbgBFKcD (ORCPT ); Thu, 6 Feb 2020 05:32:03 -0500 Received: from lhreml705-cah.china.huawei.com (unknown [172.18.7.106]) by Forcepoint Email with ESMTP id A72D42D9EF9F868C2866; Thu, 6 Feb 2020 10:32:01 +0000 (GMT) Received: from lhreml724-chm.china.huawei.com (10.201.108.75) by lhreml705-cah.china.huawei.com (10.201.108.46) with Microsoft SMTP Server (TLS) id 14.3.408.0; Thu, 6 Feb 2020 10:32:01 +0000 Received: from [127.0.0.1] (10.202.226.45) by lhreml724-chm.china.huawei.com (10.201.108.75) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256) id 15.1.1713.5; Thu, 6 Feb 2020 10:32:01 +0000 From: John Garry Subject: Query on device links To: Greg Kroah-Hartman , "Rafael J. Wysocki" CC: Saravana Kannan , "linux-kernel@vger.kernel.org" Message-ID: <7f7d9b37-3f10-fefb-db23-86c8f83e8885@huawei.com> Date: Thu, 6 Feb 2020 10:31:59 +0000 User-Agent: Mozilla/5.0 (Windows NT 10.0; WOW64; rv:68.0) Gecko/20100101 Thunderbird/68.1.2 MIME-Version: 1.0 Content-Type: text/plain; charset="utf-8"; format=flowed Content-Language: en-US Content-Transfer-Encoding: 7bit X-Originating-IP: [10.202.226.45] X-ClientProxiedBy: lhreml720-chm.china.huawei.com (10.201.108.71) To lhreml724-chm.china.huawei.com (10.201.108.75) X-CFilter-Loop: Reflected Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Hi guys, According to "Limitations" section @ https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/tree/Documentation/driver-api/device_link.rst#n110, for a managed link, lack of the supplier driver may cause indefinite delay in probing of the consumer. Is there any way around this? So I just want the probe order attempt of the supplier and consumer to be guaranteed, but the supplier probe may not be successful, i.e. does not actually bind. In my case, I would like to use device_link_add(supplier, consumer, DL_FLAG_AUTOPROBE_CONSUMER), but I find the supplier probe may fail (and not due to -EPROBE_DEFER), and my consumer remains in limbo. You may ask my I want this ordering at all - it is because in really_probe(), we do the device DMA configure before the actual device driver probe, and I just need that ordering to be ensured between devices. Thanks, John